A method for constructing a stable solid-state interface on the cathode surface of sulfur-based and selenium-based batteries

Abstract

The invention discloses a method for constructing a stable solid interface on the surface of a positive electrode of a sulfur-based or selenium-based battery. The method comprises the steps of 1) assembling a sulfur-based or selenium-based positive electrode material into a battery; 2) discharging the battery with a first-cycle discharging current when the battery is discharged for the first cycle; 3) when the battery is charged for the first circle, charging the battery with a first-circle charging current greater than the first-circle discharging current; and (4) using the battery at the circulating working current greater than the first-circle discharging current all the time in the using process of the battery. According to the method for constructing the stable solid interface on thesurface of the positive electrode of the sulfur-based and selenium-based battery, the circulating stability of an electrode material can be improved, and the capacity of rapidly charging and discharging the interior of the battery is improved at the same time.

Description

technical field [0001] The invention relates to a method for preparing a positive electrode material of a sulfur-based or selenium-based battery, in particular to a method for constructing a stable solid interface on the surface of the positive electrode of a sulfur-based or selenium-based battery. Background technique [0002] With the continuous improvement of human productivity, petrochemical energy is gradually becoming exhausted, and it is becoming more and more urgent for people to seek a new type of energy storage device with high energy density. Among them, the battery with sulfur / selenium as the positive electrode of the battery material, as a future clean energy storage device with great potential and development prospects, is undergoing technological innovation at a rapid rate. However, the development of sulfur / selenium-based batteries is limited by its own unique characteristics, that is, during the reaction process, the electrode materials will generate soluble...

AI Technical Summary

Problems solved by technology

However, the development of sulfur / selenium-based batteries is limited by its own unique characteristics, that is, during the reaction process, the electrode materials will generate soluble sulfur / selenium compounds, which will form a shuttle effect inside the battery, not only because the active material The dissolution and diffusion loss of the battery leads to a decrease in battery capacity and coulombic efficiency, and the sulfur / selenium compound is also reduced on the surface of the negative electrode (lithium, sodium or potassium), so that the negative electrode cannot provide enough electrochemically active interface to diffuse metal ions, which eventually leads to battery electrochemical deactivation

[0003] However, there are many factors that restrict the use of sulfur / selenium as the positive electrode material of the battery, such as the volume change of the active material during the reaction process, the poor conductivity of active materials such as sulfur / selenium, etc. Among them, the sulfur / selenium-based battery cannot be used as a lithium-ion battery. It is particularly important to form a stable solid-liquid interface on the surface of the positive electrode material. Because there is no stable solid-liquid interface, the sulfur / selenium-based positive electrode material will change with the reaction during the cycle, and the structure and surface of the positive electrode will continue to change, resulting in activity. The continuous loss of material eventually leads to rapid decay of battery capacity, cycle life and Coulombic efficiency

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